1. Technical Field
The present specification describes a liquid discharging head using a piezoelectric actuator and an image forming apparatus using the liquid discharging head, and more particularly, a liquid discharging head using a piezoelectric actuator and an image forming apparatus using the liquid discharging head for discharging liquid onto a recording medium to form an image on the recording medium.
2. Discussion of the Background
An image forming apparatus, such as a copying machine, a facsimile machine, a printer, or a multifunction printer having two or more of copying, printing, scanning, and facsimile functions, forms an image on a medium (e.g., a sheet) by using a liquid discharging method. In the liquid discharging method, a liquid discharging device includes a liquid discharging head (e.g., a recording head) for discharging liquid (e.g., an ink drop) onto a conveyed sheet. The liquid is adhered to the sheet to form an image on the sheet.
A known liquid discharging head is a piezoelectric type head using a piezoelectric actuator including a piezoelectric element. The piezoelectric element functions as a pressure generator or an actuator for generating pressure to compress liquid in a liquid chamber.
In one example of a related art liquid discharging head including the piezoelectric element, non-driven piezoelectric element columns are disposed on both ends of a piezoelectric element. An FPC (flexible printed circuit) having a width smaller than a width of the piezoelectric element is connected to the piezoelectric element.
Another example of the related art liquid discharging head includes a long head in which a plurality of piezoelectric element columns is groove-processed to form a piezoelectric element. A plurality of piezoelectric elements is disposed on a single base in a direction in which the plurality of piezoelectric element columns is aligned.
Higher printing speed is requested for the image forming apparatus (e.g., an ink-jet recording device) including the liquid discharging head. To increase printing speed, either liquid discharge frequency or a number of nozzles may be increased. In order to increase the liquid discharge frequency, a powerful motor needs to be controlled with increased precision to move a carriage for carrying the liquid discharging head at an increased speed. Further, the liquid discharging head needs to stably discharge liquid at an increased frequency. Therefore, the liquid discharging head may be a long head including the increased number of nozzles for discharging a liquid drop.
In such a long liquid discharging head, a plurality of piezoelectric elements, in each of which a plurality of piezoelectric element columns is disposed, is aligned. The plurality of piezoelectric element columns includes driven and non-driven piezoelectric element columns alternately provided. When the non-driven piezoelectric element columns are provided on both ends of the piezoelectric element, the non-driven piezoelectric element columns are adjacent to each other when the plurality of piezoelectric elements are aligned, resulting in varied nozzle pitches. To address this problem, another type of piezoelectric element, in which the driven piezoelectric element columns are provided on both ends of the piezoelectric element, is needed, resulting in increased manufacturing costs.
When the plurality of piezoelectric elements is aligned and a single electric supply member supplies electricity to the driven piezoelectric element columns of the plurality of the piezoelectric elements, a contact failure may occur if there is a difference between positions of an electrode of the electric supply member and the driven piezoelectric element column. When a plurality of electric supply members is provided to address this problem, mutual interference between adjacent electric supply members may occur.
Further, when a single electric supply member is connected to a single piezoelectric element, as a width of the aligned piezoelectric elements is increased in a direction in which the piezoelectric elements are aligned a width of the aligned electric supply members is also increased, thereby causing a large margin of error due to accumulated size tolerance. As a result, positional deviation of the electrode and the piezoelectric element column may occur, resulting in contact failure.